Flashing on Lee 6-hole

[knotbrush]

I intended to cast 20 lbs of 9mm 124gr TC TL boolits. This mold has been a gem for about a year and 5k of projectiles. About half way through I started to see flashing on some boolits. I cast a bunch in each hole, one hole at a time and the results were inconsistent, the problem would come and go. I examined the mold under a magnifier and couldn't see anything. I carefully brushed the pins and sockets with a fine brass brush, there was a bit of carbonized lube or other spooge around the bases of the pins. I carefully scraped the mating surfaces with a razorblade and still didn't find anything. Casting a few more drops confirmed the problem still existed but not on every hole and not on the same holes consistently. After another fifteen minutes the problem almost disappeared...almost.

I was thinking of testing with a C-clamp holding the mold closed. This mold has performed flawlessly in the past, what else can I look for?

[Larry Gibson]

I've found that many times when closing the sprue plate it will leave the blocks slightly ajar. Since developing the habit of slightly pulling the sprue plate handle back to the right (doesn't take much) so the blocks stay together I've had very little flashing on any of my 11 6 cavity moulds. It's also easy to grasp all 3 handles while sliding the mould under the furnace. This should not be done as it can cause the sprue plate to pivot the blocks apart.

Larry Gibson

[knotbrush]

I think you deserve a cookie! That's exactly what I do.

[fecmech]

I do exactly the same as Larry and reposition the spru handle after I close it.

[thehouseproduct]

Any other thoughts? I close the mold, close the sprue plate and then squeeze just the mold handles together and still get flash.

[Echo]

I have a plastic mallet in my hand when casting, mainly to knock sprue plates, but in the case of Lee 6-bangers, to tap the sprue plate fully closed.

[fecmech]

Any other thoughts? I close the mold, close the sprue plate and then squeeze just the mold handles together and still get flash.

Either you have some lead particles holding the blocks apart or when you squeeze the handles you are pushing on the spru handle in. Try moving the spru handle out slightly as the last thing you do before pouring. I also look closely at the end of the mold as I push it under the pot to see if there is any gap between the block parting surfaces.